This invention relates to the removal of fluoride impurities from a uranium hexafluoride gas stream and more particularly to the removal of fluoride impurities from a uranium hexafluoride gas stream by contacting the gas stream with a bed of uranium pentafluoride.
Previous methods for the removal of fluoride impurities from a uranium feedstock based on spent nuclear reactor fuel have involved a variety of techniques. In some instances, the feedstock prior to the formation of UF.sub.6 has been contacted with an aqueous solution. This has resulted in an increase in the volume of radioactive waste. In other instances, alkali metal fluorides in sorption beds have been used to separate the fluoride impurities from UF.sub.6. This has also resulted in an increase in radioactive waste products. In still other instances, as disclosed in U.S. Pat. No. 4,364,906, CaCO.sub.3 has been used as a trapping agent to purify the uranium gas stream. Other patents of interest are U.S. Pat. No. 3,806,579 involving distillation of UF.sub.6 and U.S. Pat. No. 4,311,678 involving the use of a brominating agent. While these techniques have provided useful results, they have not been entirely satisfactory.
Accordingly, one object of this invention is the purification of UF.sub.6 by another method or technique. A second object of the invention is the purification of UF.sub.6 without an increase in volume of waste products. Another object of the invention is the purification of UF.sub.6 by which the fluoride impurities are removed from the UF.sub.6 gas stream. An additional object of the invention is the purification of UF.sub.6 in which impurities trapped on a bed are recovered apart from UF.sub.6. These and other objects will become apparent from the following detailed description. A further object of the invention is the purification of UF.sub.6 by the use of a bed of reactive material which may be regenerated.